Retrievable casing foot valve



May 6, 1969 RETRIEVABLE CASING FOOT VALVE Filed Jan. 24, 1968 INVENTOR. JAMES H. COBBS H- rwei ATTORNEYS J. H. COBBS- 3,442,330 I United States Patent US. Cl. 166-225 6 Claims ABSTRACT OF THE DISCLOSURE This invention relates to a retrievable casing foot valve for closing a casing extending into a subterranean formation. More particularly, the invention relates to a retrievable casing foot valve including a tubular landing nipple attachable to the lower end of a casing, the landing nipple having an internal tapered circumferential seating sur face, a. tubular foot valve body receivable by the landing nipple having a tapered exterior circumferential seating portion sealably matching with the internal seating surface of the landing nipple, means upon rotation of the tubular foot valve when in seated position in the landing nipple of locking the foot valve in the landing nipple, and a valve means in the foot valve body normally closing the interior thereof and displaceable' to the open position by downwardly applied force. The casing foot valve further includes means of releasably grasping the valve body whereby the body may be rotated to release its locking engagement with the landing nipple for removal from the landing nipple.

Summary It is customary, in present drilling procedures, to set a casing in a bore hole to provide communication between the earths surface and an underground formation. In some cases the underground formation may consist of an oil or gas producing zone or the formation may be an underground cavern. It is frequently necessary to provide a valve means in the casing to prevent the flow of fluid or gases from the underground formation upward through the casing. The provision of such valve means within itself is not difficult, but frequently it is desirable that the valve means have three characteristics, that is, (l) the valve means must close to prevent the flow of fluid and gases from the underground formation upward through the casing; (2) the valve means must be capable of being opened by pressure from within the casing, either hydraulic or pneumatic, or physical pressure exerted against a valve element by pump or the like to open the valve; and (3) means must be provided whereby the valve itself can be removed by use of apparatus controllable from the earths surface to provide unobstructed access through the easing into the underground formation.

This invention provides a device which meets these three basic requirements in a simple, inexpensive and highly reliable arrangement.

Description of views FIGURE 1 is a view of the retrievable casing foot valve of this invention as applied to the lower end of a casing, showing the foot valve body portion partially in crosssection, and showing the tubular landing nipple in crosssection.

FIGURE 2 is a cross-sectional view taken along the line 22 of FIGURE 1.

FIGURE 3 is a cross-sectional view taken along the line 33 of FIGURE 1.

FIGURE 4 is a cross-sectional view taken along the line 44 of FIGURE 1.

FIGURE 5 is a fragmented view of a portion of the interior of the landing nipple as taken along the line 5-5 of FIGURE 1.

Detailed description Referring now to the drawings and first to FIGURE 1, the invention consists of three basic portions, that is, a landing nipple portion generally indicated by the numeral 10, a foot valve body portion generally indicated by the numeral 12, and a retrieving tool generally indicated by the numeral 14. The landing nipple 10 is of tubular configuration and is adaptable to be atfixed at the upper end to the lower end of a length of casing 16. The landing nipple 10 may be affixed to casing 16 by a threaded or bolted arrangement or by a welded arrangement as shown.

Landing nipple 10 includes a reduced internal diameter portion 18 forming an internal circumferential lip 20. The interior of the landing nipple 10 is further defined by lower tapered reduced diameter portion forming a seating surface 22 of truncated conical configuration.

Formed in the reduced internal diameter portion 18 of the landing nipple 10, as best shown in FIGURE 5, are L-shaped slots 24, each slot being defined by a vertical portion 24A which communicates with lip 20, and a horizontal portion 24B which is parallel to and spaced from the lip 20. While one of the slots 24 will function to accomplish the purpose of the invention, in the preferred embodiment two or more slots are equally spaced circumferentially around the interior of the landing nipple 10.

The tubular foot valve body 12 includes an enlarged external diameter portion defined in part by a seating surface 26 of truncated conical configuration which engages with and seals against the seating surface 22 of the landing nipple 10 when the foot valve body portion is positioned within the landing nipple. Formed in the exterior of the seating surface 26 are gasket grooves 28, each having gaskets therein to augment the sealing contact with the seating surface 22 of the landing nipple.

Extending perpendicularly of the exterior surface of the foot valve body 12 are spaced apart locking pins 30, there being one locking pin 30 for each groove 24 in the landing nipple. Locking pins 30 enter grooves 24 through the vertical portion 24A and, when the foot valve body 12 is in seated position relative to the landing nipple 10, rotation of the landing nipple causes the pins 30 to enter the horizontal portions 24B of the slots to lock the foot valve body to the landing nipple.

Afiixed to the exterior surface of the foot valve body above locking pins 30 is a resilient cup member 32. The cup member 32 has an outer circumferential portion which resiliently engages the interior circumferential surface 34 of the landing nipple above lip 20. The cup member 32 serves to prevent debris from falling into the slots 24.

In the illustrated arrangement, the foot valve body portion is closed at the lower end by a semispherical configured portion 36 having a multiplicity of openings 38 therein. The semispherical configured portion 36 helps guide the foot valve body portion 22 into the landing nipple when it is being placed in position.

Within the lower portion of the foot valve body portion is a reduced internal diameter seating shoulder 40 and a valved disc 42 which, when in the closed position, sealably engages the seating shoulder 40. The valve disc is of diameter larger than the internal diameter of the seating shoulder and is axially positionable within the tubular foot valve body below the seating shoulder and normally in sealing engagement with the seating shoulder. Afiixed to the valve disc is a coaxial, perpendicular and downwardly extending valve stem 44. Extending upwardly from the interior lower end of the closure portion 36 is a tubular stern guide 46 which telescopically and slidably receives the valve stem 44 permitting the valve stem to move up and down so that the valve disc 42 is moved into and out of sealing engagement with the seating shoulder 40. To bias the valve disc 44 to closed position, a spring 48 is compressibly positioned around the valve stem 44 and beneath the disc 42 urging the disc upwardly into seating engagement with seating shoulder 40. When the valved disc 42 is pushed downwardly communication between the interior and exterior of the foot valve body portion 12 is provided through openings 38. Gasketed grooves 50 in disc 42 help insure a sealed engagement with the seating shoulder 40 and the interior of the foot valve body portion 12 when the disc is in closed position.

Aflixed to the exterior surface of the upper portion of the foot valve body portion 12 is one or more radial extending grasping pins 52.

Retrieving tool 14 includes a tubular lower portion of an internal diameter to telescopically receive the exterior diameter of the upper portion of the foot valve body 12. Formed in the tubular lower portion of the retrieving tool is one or more grooves 56 of a configuration substantially of the shape of an inverted I, that is, including a vertical portion 56A, a horizontal portion 56B, and a shorter vertical portion 56C spaced from vertical portion 56A. There is one groove 56 for each grasping pin 52. Affixed to the upper end of retrieving tool 14 is tubing 58 which extends to the earths surface providing means for lowering the retrieving tool 14 in the hole and for rotation of the tool.

Operation When a drill hole is completed to an underground formation, whether an oil, gas or water bearing formation, or a formation consisting of a cavern or other subterranean structure, casing 16 having landing nipple is placed in position. When it is desired to close communication between the subterranean formation and the interior of the casing, foot valve body 10 is secured to the retrieving tool 14 by inserting the upper portion of the foot valve body into the retrieving tool and rotating it so that grasping pins 52 extend within the portion 56C of the groove. By means of tubing 58 the retrieving tool having the foot valve body attached thereto is lowered into the casing 16. When the foot valve body engages the landing nipple, the retrieving tool 14 is rotated by means of tubing 58 until the locking pins 30 align with and enter into the vertical portion 24A of slots 24 in the landing nipple. When the pins 30 have passed to the lower end of slot 24, the foot valve body may then be rotated by rotation of tubing 58 to move locking pins 30 into the horizontal portion 24B of the slots, thereby locking the foot valve body in sealed position in the landing nipple. The retrieving tool 14 may then be rotated in the opposite direction to align grasping pins 52 with the vertical portion 56A of the slots and the retrieving tool can then be pulled upwardly and, if desired, removed from the casing 16. This leaves the foot valve body in sealed position in the landing nipple. The casing 16 is then sealed against entrance of fluid or gas from the subterranean formation by valve disc 42.

If it is desired to provide communication between the interior of the casing and the subterranean formation, a pump or other physical object may be lowered into the casing until it engages the valve disc 42. Further downward pressure compresses spring 48 and opens communication with the interior of the casing through openings 38. It can be seen that the valve disc 42 can also be opened by application of hydraulic or pneumatic pressure within the casing exceeding the pressure outside the casing. Any time the physical force or hydraulic force tending to open the valve disc 42 is removed, the valve disc closes and prevent fluid or gas from flowing out of the subterranean formation.

If it is desired to remove the foot valve body 12, the retrieving tool 14 is lowered into the casing 16 and, by rotation of the tubing 58, slots 56 are aligned with grasping pins 52. The foot valve can then be rotated to align locking pins 30 with the vertical portion 24A of slots 24. Upward force then applied by the retrieving tool lifts the valve body out of the landing nipple and leaves the landing nipple open for the passage therethrough of other tools or devices, or for unobstructed fluid communication with the subterranean formation.

While the invention has been described with a certain degree of particularity, it is manifest that many changes may be made in the details of construction and arrangement of components without departing from the spirit and scope of this disclosure. It is understood that this invention is not limited by the abstract herein, nor the summary, nor the embodiment which has been set forth for purposes of exemplifying the invention, but the invention is to be limited only by the scope of the appended claim or claims, including the full range of equivalency to which each element or step thereof is entitled.

What is claimed:

1. A retrievable casing foot valve for closing a casing extending into a subterranean formation comprising:

a tubular landing nipple attachable at the upper end thereof to the lower end of a casing, the landing nipple having a reduced diameter internal portion forming an internal circumferential lip, having at least one slot formed in the interior surface of the reduced internal diameter portion, the slot having a vertical portion communicating with the circumferential lip and a lower horizontal portion, the interior of the landing nipple being further defined by a lower tapering reduced diameter portion forming a seating surface of truncated conical configuration;

a tubular foot valve body receivable by said landing nipple having a tapering, enlarged diameter exterior portion forming a seating surface of truncated conical configuration engageable with said landing nipple sealing surface in sealing relationship;

at least one locking pin extending radially from the exterior surface of said tubular foot valve and engageable with said slot in the interior surface of said landing nipple whereby said locking pin may enter said horizontal portion of said slot by way of said vertical portion to lock said foot valve body sealably within said landing nipple;

a valve means within said foot valve body normally closing the interior thereof, said valve means being displaceable to open position by downward force; and

means of releasably grasping the foot valve body whereby said body may be rotated to move said pin into alignment with the vertical portion of said groove and for removing said foot valve body from within said landing nipple.

2. A retrievable casing foot valve according to claim 1 including a resilient cup member aflixed to said foot valve body 5 above said pin, said cup member having an outer circumference portion resiliently engaging the interior circumferential surface of said landing nipple when the foot valve body is in sealed position in said landing nipple, the cup member serving to prevent debris from falling into said slot in said landing nipple.

3. A retrievable casing foot valve according to claim 1 wherein said means of releasably grasping said foot valve body includes at least one grasping pin extending radially from the upper exterior surface of said foot valve body memher;

a retrieving tool having a tubular lower portion of an internal diameter to telescopically receive the exterior diameter of said foot valve body, said retrieving tool having a slot of inverted J configuration, said slot receiving said grasping pin when said retrieving tool is lowered onto said foot valve body; and

means of rotating said retrieving tool when in engagement with said foot valve body to rotate the same to 6 align said locking pin with said vertical portion of 6. A retrievable casing foot valve according to claim said slot in said landing nipple interior surface and 5 including means of raising said retrieving tool to remove said a valve, stem affixed to and extending coaxially and foot valve body from within said landing nipple. perpendicularly downwardly from said valve disc; 4. A retrievable casing foot valve according to claim 5 a tubular stem guide extending upwardly from the 1 wherein said valve means includes internal lower closed end of said foot valve body and a reduced internal diameter seating shoulder in said slidably receiving said valve stem; and wherein said tubular foot valve body; spring means includes a a valve disc of diameter larger than the internal dicompressed coil spring means receiving said valve stem ameter of said seating shoulder and axially position- 10 urging said valve disc into upward contact with said able within said tubular foot valve body below said seating shoulder.

seating shoulder and normally in sealing engagement with said seating shoulder to close said tubular foot References Clted valve body against fluid flow therethrough and to UNITED STATES PATENTS permit fluid flow therethrough when said valve disc 1,508,586 9/1924 Baker 166 224 s displaced from said seating shoulder; and 1 59 47 2 192 Black Spring BaHS normally urging Said valve disc iIItO 2 153 12 4 1939 Newton 1 224 sealing engagement with said seating shoulder. 3,087,551 4 /1963 Kerver 166 224 5. A retrievable casing foot valve according to claim 4 3,106,932 10/1963 Chisholm 166 224 X Wherem 3,314,481 4/1967 Willman et a1. 166205 said foot valve body is closed at the lower end thereof and includes at least one opening in the side thereof DAVID R BROWN, Primary E i adjacent and below said seating shoulder whereby when said valve is displaced downwardly away from US. Cl. X.R. said seating shoulder fluid passage is provided through 166242 said opening and said seating shoulder into the interior of said foot valve body. 

